function [ds1_norm,ds2_norm,v]= normalize_data(ds1,ds2)
    ds1_norm = ds1;
    ds2_norm = ds2;
    if size(ds1,2)~=size(ds2,2)
        error(['The dimension of ds1, ',size(ds1,2),', is not the same as ds2,',size(ds2,2)])
        v = 0;
        return 
    end 
    v = zeros(1,size(ds1_norm,2));
    for i=1:size(ds1,2)
        ds = [ds1(:,i);ds2(:,i)];
        v(i) = std(ds);
        ds1_norm(:,i) = ds1_norm(:,i)/v(i);
        ds2_norm(:,i) = ds2_norm(:,i)/v(i);
    end
end